U.S. patent application number 14/313616 was filed with the patent office on 2014-10-16 for downhole drilling assembly.
This patent application is currently assigned to HALLIBURTON ENERGY SERVICES, INC.. The applicant listed for this patent is Halliburton Energy Services, Inc.. Invention is credited to Bachar Boussi, Andrew McPherson Downie, Pascal Michel Vitale.
Application Number | 20140305711 14/313616 |
Document ID | / |
Family ID | 40639857 |
Filed Date | 2014-10-16 |
United States Patent
Application |
20140305711 |
Kind Code |
A1 |
Downie; Andrew McPherson ;
et al. |
October 16, 2014 |
DOWNHOLE DRILLING ASSEMBLY
Abstract
A downhole stabiliser (5), such as a drill motor stabiliser,
comprises at least one reaming means and/or reinforcing means (10).
The present invention also relates to an assembly (30), such as a
downhole drilling assembly (31), comprising at least one such
stabiliser (5) and/or a drill bit (40,41) comprising a gauge bit
(42) at or near a drilling end (45) thereof, and a connection means
(46) for connecting the drill bit (40,41) to a drill motor assembly
(60), wherein the drill bit gauge (42) comprises a substantially
cylindrical portion having a length less than or equal to
approximately 1.0 times the nominal bit diameter. The present
invention also relates to a novel locking mechanism (80), such as a
lock and key mechanism, to allow locking of a shaft (70'), e.g. a
motor drive shaft (71'), through or together with a stabiliser
(5').
Inventors: |
Downie; Andrew McPherson;
(Fife, GB) ; Vitale; Pascal Michel; (Eybens,
FR) ; Boussi; Bachar; (Houston, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Halliburton Energy Services, Inc. |
Houston |
TX |
US |
|
|
Assignee: |
HALLIBURTON ENERGY SERVICES,
INC.
Houston
TX
|
Family ID: |
40639857 |
Appl. No.: |
14/313616 |
Filed: |
June 24, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13257620 |
Jan 23, 2012 |
|
|
|
PCT/GB2010/000502 |
Mar 19, 2010 |
|
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14313616 |
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Current U.S.
Class: |
175/92 ;
175/325.1; 175/408 |
Current CPC
Class: |
E21B 7/068 20130101;
E21B 17/04 20130101; E21B 17/1078 20130101; E21B 10/26 20130101;
E21B 17/10 20130101; E21B 4/00 20130101; E21B 17/1092 20130101 |
Class at
Publication: |
175/92 ; 175/408;
175/325.1 |
International
Class: |
E21B 17/10 20060101
E21B017/10; E21B 4/00 20060101 E21B004/00; E21B 17/04 20060101
E21B017/04 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 20, 2009 |
GB |
0904791.1 |
Claims
1. An assembly comprising a drill bit, wherein the drill bit
comprises a drill bit gauge at or near a drilling end thereof, and
a connection means for connecting the drill bit to a motor shaft of
a drill motor assembly, wherein the connection means is configured
for engaging with a receiving portion provided at or near a lower
end portion of the motor shaft, the motor shaft being provided
within or inside the motor body portion, wherein the drill bit
gauge comprises a substantially cylindrical portion having a length
less than or equal to approximately 1.0 times the nominal bit
diameter.
2. An assembly according to claim 1, wherein the drill bit gauge
comprises a substantially cylindrical portion having a length in
the range of 1 inch (2.5 cm) to 1.0 times the nominal bit
diameter.
3. An assembly according to claim 1, wherein the drill bit gauge
has a length in the range of 1'' to 8'' (2.5 to 20.3 cm).
4. An assembly according to claim 3, wherein the drill bit gauge
has a length in the range of 2'' to 6'' (5.1 to 15.2 cm).
5. An assembly according to any of claim 1, wherein the distance
between a lower or drilling end of the motor body and the drill bit
gauge is in the range of 1'' to 8'' (2.5 to 20.3 cm).
6. An assembly according to claim 5, wherein the distance between a
lower or drilling end of the motor body and the drill bit gauge is
in the range of 2'' to 6'' (5.1 to 15.2 cm).
7. An assembly according to claim 1, wherein the drill bit is
devoid of a bit sleeve.
8. An assembly according to claim 1, wherein the connection means
comprises an externally threaded pin configured for engaging and/or
connecting with an internal thread of a lower end portion of the
shaft.
9. An assembly according to claim 1, wherein the drill bit
comprises a neck portion provided at or near an upper end of the
gauge bit and configured to allow gripping of the drill bit.
10. An assembly according to claim 1, wherein the drill bit
comprises a diamond-impregnated carbide material.
11. An assembly according to claim 1, comprising at least one
stabiliser or centraliser.
12. An assembly according to claim 11, wherein the assembly
comprises a downhole drilling assembly.
13. An assembly according to claim 11, wherein the assembly further
comprises a drill motor assembly.
14. An assembly according to claim 13, wherein the stabiliser is
provided at a lower end of the drill motor assembly nearest a drill
end thereof.
15. An assembly according to claim 13, wherein the drill motor
assembly comprises a tubular motor body portion configured for
selective rotational movement, and a motor shaft provided within or
inside the tubular motor body portion.
16. An assembly according to claim 15, wherein the tubular motor
body portion is attached and/or rotationally connected to the
stabiliser.
17. An assembly according to claim 13, wherein the assembly is
devoid of a connector or bit box between the drill bit and a lower
or drilling end of the drill motor assembly.
18. An assembly according to claim 15, wherein a lower end portion
of the stabiliser is substantially level or flush with a lower end
portion of the motor shaft and/or motor body portion.
19. An assembly according to claim 15, wherein the shape of the
stabiliser is substantially concentric in relation to the motor
shaft and/or motor body portion.
20. An assembly according to claim 11, wherein an external diameter
of the stabiliser is substantially identical to the full gauge
diameter of the drill bit, i.e. 0 to -1/8'' (0.3 cm), of the
nominal hole size.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a division of U.S. patent application
Ser. No. 13/257,620 filed on Sep. 20, 2011, which is the U.S.
national phase of PCT/GB2010/000502 filed Mar. 19, 2010, which
claims priority of Great Britain Patent Application 0904791.1 filed
on Mar. 20, 2009.
FIELD OF THE INVENTION
[0002] The present invention relates to a downhole stabiliser, such
as a drill motor stabiliser, and to a downhole assembly comprising
such a stabiliser.
[0003] The present invention also relates to improved stabilisation
devices for drill motors, and particularly, but not exclusively, to
stabilisation devices for use with steerable high speed motors for
operation in a wellbore.
[0004] The present invention also relates to a novel locking
mechanism, such as a lock and key mechanism to allow locking of a
shaft, e.g. a motor drive shaft, through or together with a
stabiliser, e.g. a drill motor stabiliser, and in particular,
though not exclusively, for attaching, removing and/or securing a
drill bit, such as a short gauge drill bit to/from a lower end of
the shaft.
BACKGROUND OF THE INVENTION
[0005] Various types of downhole motors, including positive
displacement motors and turbodrills may be suitable to drive a
drill bit within a borehole, e.g. during drilling of the borehole.
Steerable high speed motors, also known as turbodrills or turbines,
are a commonly employed type of downhole motor and have become well
known in the field of downhole drilling.
[0006] During the development of steerable high speed motors, it
was recognised that at high speeds it was necessary that the motor
and bit assembly be stabilised in order to reduce or eliminate
wellbore tortuosity--commonly known as spiralling. This spiralling
motion which can occur at high speeds can seriously reduce the
drilling rate, as well as cause excessive wear of the various parts
of the motor assembly. This spiralling effect can be particularly
severe in the case of certain types of geological formations in
which the bore is being formed.
[0007] In a typical drilling assembly the drill bit is connected to
a motor shaft located inside a motor body.
[0008] The direction of formation of the wellbore may be
controlled, e.g. by providing a bend, a deviating device, or an
eccentric stabiliser, located at a suitable position of the
assembly.
[0009] During normal drilling the motor body portion is rotated at
a lower speed than the speed of the drill bit, thereby mitigating
the effect of the deviating device. On the other hand, when
directional or lateral drilling is required, the deviating device
of the assembly is adjusted in a desired direction and held
stationary, with the drill bit being rotated at high speed by the
downhole motor.
[0010] In order to maximise the wellbore deviation, the so-called
bit overhang (that is the distance from the lower end, e.g. lower
bearing or lower stabiliser, on the motor body housing to the
operating face of the drill bit) should be kept to a minimum.
[0011] Typically the majority of drill bits comprises a pin
connection (Male) with an API thread to mate with a box connection
(Female) API thread on the mating component, which may be a drill
collar, sub or motor shaft. However, in turbine drilling it has
become common practice for the thread connection to be reversed,
the bit being provided with the box connection.
[0012] In downhole drilling, the terms "short gauge bits" or "long
gauge bits" refer to the stabilising or guiding portion of the
outer diameter that is used for the purposes of final trimming and
guidance of the bit within the hole created by the bit. The gauge
may include a sleeve to extend the guiding portion of the bit over
a longer length. This sleeve can be made as an integral part of the
bit structure. The extended sleeve portion typically has a diameter
of +/- 1/32'' of the nominal bit diameter.
[0013] In the art, a short gauge bit is understood to mean a drill
bit with an outer cylindrical portion the length of which measures
approximately 1 inch to 1.0 times the nominal bit diameter. This
contrasts with the so-called long gauge bits which may have
cylindrical portions the lengths of which are in excess of 1 times
the bit diameter. Furthermore, the so-called long gauge bits are
often fabricated from separate pieces and have a short cylindrical
portion, which forms part of the bit head and a second cylindrical
portion formed from a separate sleeve and joined to the bit head.
It is understood that the two cylindrical portions combine such
that the cylindrical portion length is in excess of 1 times the
nominal bit diameter. The two cylindrical portions are
substantially of the same diameter but can be slightly different;
approximately 1/32'' difference is possible due to normal
manufacturing tolerance variations.
[0014] Short gauge bits have been used in drilling assemblies.
However, known assemblies comprising a short gauge bit involved the
use of a stabiliser between the gauge bit and the end of the motor
body. While this type of arrangement is effective in stabilising
the bit, the bit overhang is increased significantly thereby
reducing the steerability of the motor assembly.
[0015] Current turbines tend to employ drilling bits having long
total gauge lengths, typically from 1 times the nominal bit
diameter to more than 2 times the nominal bit diameter. This has
become necessary to ensure a smooth wellbore is produced. However,
this introduces a risk that the drill bit may become stuck in the
wellbore, and also increases the cost of the drill bit.
[0016] Recent developments in drill bits have led to motor
assemblies which no longer require the presence of a bit box
between the lower end of the motor shaft and the drill bit. Such an
arrangement is described in U.S. Pat. No. 5,853,053 (GILCHRIST et
al.). While the assembly disclosed therein provides a reduction in
the bit overhang, some of the associated disadvantages may include
premature wear of the stabiliser, and a relatively high risk that
the long gauge drill bit may become stuck in the borehole.
[0017] It is an object of at least one embodiment of at least one
aspect of the present invention to obviate and/or mitigate one or
more disadvantages in the prior art.
[0018] It is an object of at least one embodiment of at least one
aspect of the present invention to provide a downhole drill motor
stabiliser comprising reaming features or reaming means provided at
or near at least a front portion of at least one blade of the
stabiliser.
[0019] It is an object of at least one embodiment of at least one
aspect of the present invention to provide a drill bit comprising a
gauge bit, e.g. a short gauge bit, and a connection means for
connecting the drill bit to a drill motor assembly.
[0020] It is an object of at least one embodiment of at least one
aspect of the present invention to provide a downhole drilling
assembly comprising an improved stabiliser, and optionally a drill
bit such as a short gauge drill bit, and a motor assembly.
[0021] It is an object of at least one embodiment of at least one
aspect of the present invention to provide a locking means or lock
and key mechanism for locking of a motor drive shaft through or
together with a motor stabiliser, and beneficially allowing ease of
handling, and attachment and/or removal of a drill bit to/from the
motor drive shaft.
[0022] It is an object of at least one embodiment of at least one
aspect of the present invention to provide a downhole drilling
assembly comprising the locking means or lock and key
mechanism.
SUMMARY OF THE INVENTION
[0023] According to a first aspect of the present invention there
is provided a stabiliser comprising at least one reaming means
and/or reinforcing means.
[0024] In the art the term stabiliser is known and understood.
However, it will be understood that other equivalent terms may be
used in the art, e.g. centraliser.
[0025] The stabiliser may comprise a downhole stabiliser.
[0026] Advantageously, the stabiliser may be a drill motor
stabiliser.
[0027] The stabiliser may comprise one or more blades, e.g. a
plurality of blades, e.g. longitudinally extending blades, on or
around an outer surface thereof, e.g. circumferentially spaced.
[0028] Alternatively, the one or more blades, e.g. plurality of
blades, may be profiled, e.g. oblique or waved relative to an axis
of rotation of the stabiliser.
[0029] The stabiliser may comprise a cylindrical body, and the
outer surface may comprise an outer surface of the cylindrical
body.
[0030] Each blade may comprise at least one top or outermost
portion or surface.
[0031] Each blade may also comprise at least one sloped or inclined
portion or surface extending between the at least one top or
outermost portion or surface of the blade and a body portion or end
portion of the stabiliser, e.g. of the cylindrical body, at or near
a first or lower or drilling end and/or a second or upper end
thereof.
[0032] Typically, each blade may comprise at least one edge between
the at least one top portion or surface and the at least one sloped
portion or surface thereof.
[0033] Beneficially, the reaming means may be provided on at least
one blade of the stabiliser.
[0034] The stabiliser may comprise at least one first reaming means
and/or reinforcing means provided at least at or near a first or
lower end portion of the stabiliser, which first end is nearest a
drill end thereof, in use. By such provision, any variation and/or
imperfection in the drilling profile arising from displacement of
the drill bit from a central axis during drilling may be corrected
by reaming of the wellbore by the centraliser, thereby improving
the quality of the wellbore.
[0035] The stabiliser may further comprise at least one second
reaming means and/or reinforcing means provided at least at or near
a second or upper end portion of the stabiliser, which second end
is farthest from a drill end thereof, in use. By such provision,
further reaming of the wellbore may be performed by rotation of the
stabiliser during removal of a drilling assembly or `Pulling Out Of
Hole` (`POOH`).
[0036] Preferably, the first and/or second reaming means may
comprise means, e.g. reaming blocks, protruding or extending at
least partially from a top surface of at least one blade over or
onto a sloped surface thereof.
[0037] The first and/or second reaming means may each have an
outermost surface which may be substantially planar. A portion of
the outermost surface of the first and/or second reaming means may
be substantially flush or level with the outermost surface of the
blade(s) upon which they are provided. A further portion of the
outermost surface of the first and/or second reaming means may be
provided radially outward of the respective inclined surface.
[0038] The stabiliser may further comprise at least one third
reaming means and/or reinforcing means provided on at least one
portion, e.g. the sloped portion, of at least one blade. By such
provision, in use, the sloped portion of a blade may be protected
from excessive or premature wear, e.g. by "undercutting".
[0039] The stabiliser may further comprise at least one fourth
reaming means and/or reinforcing means provided on at least a top
portion or surface of at least one blade thereof.
[0040] Typically, the third and fourth reaming means and/or
reinforcing means may be substantially level or flush with an outer
surface at least one blade of the stabiliser.
[0041] The stabiliser may further comprise at least one fifth
reaming means and/or reinforcing means provided at least partially
along at least one longitudinal edge of at least one blade.
[0042] Conveniently, the at least one fifth reaming means and/or
reinforcing means may provided at least partially along or near a
longitudinal edge of at least one blade facing substantially
towards a direction of rotation of the stabiliser, in use. By such
provision, reaming performance may be improved and/or the at least
one blade may be protected from excessive or premature wear, e.g.
by "undercutting".
[0043] Typically, the first, second, third and fifth reaming means
and/or reinforcing means may comprise blocks and/or may be made
from a diamond-impregnated material, e.g. a diamond-impregnated
tungsten carbide material.
[0044] Typically, the fourth reaming and/or reinforcing means may
be made from an optionally diamond-impregnated tungsten carbide
material.
[0045] Beneficially, the fourth reaming means and/or reinforcing
means may comprise blocks, e.g. a mixture of shaped blocks, which
blocks may be made from a tungsten carbide material and/or from a
diamond-impregnated tungsten carbide material.
[0046] Reaming blocks or reinforcing blocks made from different
materials may be provided with different shapes.
[0047] Typically, reaming blocks made from a diamond impregnated
tungsten carbide material are provided in a circular, hexagonal, or
octagonal shape, and reinforcing blocks made from a non-reinforced
tungsten carbide material may be provided in a rectangular
shape.
[0048] Preferably, the reaming means and/or reinforcing means may
be provided on one blade of the stabiliser.
[0049] Alternatively, the reaming means and/or reinforcing means
may be provided on more than one blade, e.g. every blade, of the
stabiliser.
[0050] Preferably, the reaming means and/or reinforcing means may
be provided on the same blade of the stabiliser.
[0051] Alternatively, each of first, second, third, fourth and
fifth reaming means and/or reinforcing means may be provided
independently on one or more blades of the stabiliser.
[0052] The first, second, third, fourth and/or fifth reaming means
and/or reinforcing means may comprise a combined reaming and
reinforcing means.
[0053] It is understood that the reaming features provided on the
stabiliser of the present invention may fulfil their function when
the stabiliser is in rotational motion, e.g. during normal drilling
mode.
[0054] Advantageously, the first, second, third, fourth and/or
fifth reaming means and/or reinforcing means may be made of a
material harder than a/the body of the stabiliser.
[0055] Typically, the stabiliser may be made from a low carbon
alloy steel, e.g. a "AISI4145" steel.
[0056] Advantageously, the stabiliser may be a downhole drill motor
stabiliser.
[0057] According to a second aspect of the present invention there
is provided a drill bit comprising a gauge bit at or near a
drilling end thereof, and a connection means for connecting the
drill bit to a drill motor assembly, wherein the drill bit gauge
may comprise a substantially cylindrical portion having a length
less than or equal to approximately 1.0 times the nominal bit
diameter, and typically in the range of 1 inch to 1.0 times the
nominal bit diameter.
[0058] By such provision the drill bit may be termed a "short gauge
bit".
[0059] The drill bit gauge may have a length in the range of 1'' to
8'', typically 2'' to 6''.
[0060] Beneficially, the drill bit may be devoid of a bit sleeve.
By such provision the drill bit may rely only on the integral
matrix gauge for stabilisation. Further, the bit overhang may be
reduced significantly thereby improving the steerability of the
motor assembly and diminishing the likelihood of the drill bit
becoming stuck. Further still, in the event that the drill bit
becomes stuck, the force required to free the drill bit may be
reduced. In the event that the drill bit may not be freed,
repetitive application of pulling and/or jarring force on the drill
bit may cause the drill bit to break, thereby avoiding the need to
abandon a section of the bottom hole assembly and/or of the
wellbore, thus reducing operating costs in such circumstances.
[0061] The connection means, e.g. a thread connection, may connect
the drill bit to a motor shaft of the drill motor assembly.
[0062] Typically, the connection means, e.g. a thread connection,
may comprise an externally threaded pin configured for engaging and
connecting with a receiving portion, e.g. an internal thread, of a
lower end portion of the shaft. By such provision, the need for a
connector, e.g. a bit box, between the drill bit and the end of the
drill motor assembly, e.g. motor shaft, is eliminated.
[0063] Conveniently, the drill bit may further comprise a neck
portion provided, e.g. at or near an upper end of the gauge bit to
allow gripping, e.g. by a bit gripper.
[0064] Typically, the drill bit may be made from a
diamond-impregnated carbide material with a suitable binder
material.
[0065] According to a third aspect of the present invention there
is provided an assembly, such as a downhole assembly, comprising at
least one stabiliser according to the first aspect of the present
invention, and/or comprising a drill bit according to the second
aspect of the present invention.
[0066] Advantageously the assembly may comprise a drilling
assembly.
[0067] The assembly may further comprise a drill motor
assembly.
[0068] Preferably, the stabiliser may be provided at a lower end of
the drill motor assembly, i.e. an end nearest a drill end
thereof.
[0069] Typically, the drill motor assembly may comprise a tubular
motor body portion adapted for selective rotational movement, a
motor shaft provided within or inside the tubular motor body
portion, and a drill bit attachment means provided at or near a
lower end portion of the motor shaft.
[0070] Typically also, the tubular motor body portion may be
attached and/or rotationally connected to the stabiliser. By such
provision, rotational motion of the motor body portion may cause
rotational motion of the stabiliser, e.g. during normal drilling.
Conversely, absence of rotational motion of the motor body portion
e.g. during directional or lateral drilling, may cause the
stabiliser to remain stationary in relation to the motor shaft.
[0071] Typically, a lower end portion of the shaft may be provided
with a receiving portion, e.g. an internal thread into which is
received the connection means, e.g. a thread connection such as an
externally threaded pin of the drill bit.
[0072] The assembly may be devoid of a connector, e.g. a bit box,
between the drill bit and a lower or drilling end of the drill
motor assembly, e.g. motor shaft.
[0073] Conveniently, a lower end portion of the stabiliser may be
substantially level or flush with a lower end portion of the motor
shaft and/or motor body portion.
[0074] Conveniently, the drill bit may further comprise a neck
portion provided, e.g. at or near an upper end of the gauge bit to
allow gripping, e.g. by a bit gripper.
[0075] The shape of the stabiliser may be substantially concentric
in relation to the motor shaft and/or motor body portion.
[0076] Alternatively the shape of the stabiliser may be acentric or
eccentric in relation to the motor shaft and/or motor body
portion.
[0077] The external diameter of the stabiliser may be substantially
identical to the full gauge diameter of the drill bit, i.e. 0 to
-1/8'', of the nominal hole size.
[0078] Alternatively, the stabiliser may display an offset such
that at least one offset blade of the stabiliser may sweep a radius
equal to or greater than the bit gauge radius. Typically, the
offset radius may be 0 to +3 mm of the bit gauge radius.
[0079] The drill motor assembly may comprise a deviating device,
e.g. an offset stabiliser or a bend.
[0080] Advantageously, when the shape of the stabiliser of the
present invention is acentric or eccentric in relation to the motor
shaft and/or motor body portion, the acentric or eccentric
stabiliser may be alignable with and/or relative to the deviating
device. By such provision, deviation of the drilling assembly by
the deviating device may be adjusted, improved and/or increased by
aligning the acentric or eccentric stabiliser with and/or relative
to the deviating device.
[0081] Beneficially, the drill bit may be devoid of a bit sleeve.
By such provision the drill bit may rely only on the integral
matrix gauge for stabilisation, and the bit overhang may be reduced
significantly thereby improving the steerability of the motor
assembly.
[0082] Typically, the drill bit may comprise a substantially
cylindrical portion having a length less than or equal to
approximately 1.0 times the nominal bit diameter, and typically in
the range of 1 inch to 1.0 times the nominal bit diameter. By such
provision the drill bit may be termed a "short gauge bit".
[0083] The drill bit gauge may have a length in the range of 1'' to
8'', typically 2'' to 6''.
[0084] Typically, the distance between a lower or drilling end of
the motor body, e.g. motor shaft and/or of the stabiliser and the
bit gauge may be in the range of 1'' to 8'', typically 2'' to
6''.
[0085] Typically, the drill bit may be made from a
diamond-impregnated carbide material with a suitable binder
material.
[0086] Typically the drilling assembly may be a downhole drilling
assembly.
[0087] According to a fourth aspect of the present invention there
is provided a lockable means or lock and key mechanism adapted for
locking a drive shaft through, together with or relative to a
stabiliser.
[0088] Beneficially the lockable means is adapted to temporarily
and/or releasably lock the drive shaft and the stabiliser.
[0089] Advantageously, the drive shaft is a motor drive shaft
and/or the stabiliser is a drill motor stabiliser.
[0090] By such provision a lower end portion of the shaft provided
underneath or inside the stabiliser may be held in position while
attaching or detaching a drill bit to/from the shaft.
[0091] Typically, the lockable means or lock and key mechanism may
comprise a lock means and a key means.
[0092] The lock means may comprise at least one opening, aperture
or slot provided in or through a portion of the stabiliser, and at
least one receiving or lock portion provided on at least one
portion of the motor drive shaft.
[0093] Conveniently, in use, the or one of the at least one
openings of the stabiliser may be aligned with the or one of the at
least one receiving or lock portions of the motor shaft.
[0094] The at least one opening may be openably covered or
protected with covering means, e.g. a flap or cover. Such may seek
to prevent, in use, ingress, egress or gathering of debris or
drilling particles in or near the opening.
[0095] Typically, the key means may comprise at least one handling
portion and at least one engaging portion.
[0096] Conveniently, the shape and size of the at least one opening
portion may be such that the at least one engaging portion of the
key means may be inserted therethrough.
[0097] Conveniently, the at least one receiving or lock portion of
the shaft may be adapted for receiving the at least one engaging
portion of the key means.
[0098] Typically, the at least one receiving or lock portion of the
shaft may comprise e.g. a slot, and the at least one engaging
portion of the key means may be, e.g. T-shaped.
[0099] Typically, the shaft may be provided with one or more, e.g.
two, receiving or lock portions, optionally diametrically opposite
one another.
[0100] Typically also, the stabiliser may be provided with one or
more, e.g. two, openings.
[0101] Preferably, the locking means or lock and key mechanism may
be adapted for a downhole drill motor assembly.
[0102] Preferably, the drill motor stabiliser may be a stabiliser
according to the first aspect of the present invention.
[0103] According to a fifth aspect of the present invention there
is provided a downhole drilling assembly comprising at least one
lockable means or lock and key mechanism according to the fourth
aspect of the present invention.
[0104] Preferably, the downhole drilling assembly may further
comprise a stabiliser according to the first aspect of the present
invention and/or a drill bit according to the second aspect of the
present invention, and optionally a drill motor assembly.
[0105] According to a sixth aspect of the present invention there
is provided a stabiliser comprising at least one opening, aperture
or slot of the lock means of the lockable means or lock and key
mechanism according to the fourth aspect of the present
invention.
[0106] Preferably, the stabiliser is a stabiliser according to the
first aspect of the present invention.
[0107] According to a seventh aspect of the present invention there
is provided a key means for locking a drive shaft through, together
with or relative to a stabiliser.
[0108] According to an eighth aspect of the present invention there
is provided a shaft comprising at least one receiving or lock
portion, e.g. a slot, adapted for receiving at least one engaging
portion of the key means of the lockable means or lock and key
mechanism according to the fourth aspect of the present
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0109] Embodiments of the present invention will now be described
by way of example only, and with reference to the accompanying
drawings, which are:
[0110] FIG. 1 a side view of a drill motor stabiliser according to
a first embodiment of the present invention;
[0111] FIG. 2 an enlarged side view of a drilling end of the
stabiliser of FIG. 1;
[0112] FIG. 2a an enlarged cross-sectional view of part of the
drilling end of FIG. 2;
[0113] FIG. 3 a perspective view of an upper part of the stabiliser
of FIG. 1;
[0114] FIG. 4 a side view of an alternative embodiment of the drill
motor stabiliser of FIG. 1, showing an eccentric stabiliser.
[0115] FIG. 5 a perspective view of a drill bit according to a
second embodiment of the present invention;
[0116] FIG. 6 a side view of a first drilling assembly comprising
the stabiliser of FIG. 1 and the drill bit of FIG. 5;
[0117] FIG. 7 a side view of a second drilling assembly comprising
a modified stabiliser similar to that of the stabiliser of FIG.
1;
[0118] FIG. 8 a further side view of the drilling assembly of FIG.
7 with a drill bit removed and a key means in an engaged
position;
[0119] FIG. 9 a front perspective view of a lower end of a motor
drive shaft and stabiliser of the drilling assembly of FIG. 7,
showing the key means engaged with a locking means;
[0120] FIG. 10 a cut-away side view of a lower end of the drilling
assembly (stabiliser not shown) of FIG. 7, showing the key means
engaged with the locking means; and
[0121] FIG. 11 a side view of the drilling assembly of FIG. 6 or
FIG. 7 with a drill bit removed.
DETAILED DESCRIPTION OF DRAWINGS
[0122] Referring to FIGS. 1 to 4 there is shown a drill motor
stabiliser 5 according to a first embodiment of the present
invention. The stabiliser 5 comprises reaming means and/or
reinforcing means 10.
[0123] The stabiliser 5 comprises a plurality of blades 20, e.g.
longitudinally extending blades, on or around an outer surface 4
thereof, e.g. circumferentially spaced.
[0124] The stabiliser 5 comprises a cylindrical body 8, and the
outer surface 4 comprises an outer surface of the cylindrical body
8. Each blade 20 comprises at least one top or outermost portion or
surface 22.
[0125] Each blade 20 also comprises at least one sloped or inclined
portion or surface 23 extending between the at least one top or
outermost portion or surface 22 of the blade 20 and a body portion
8 or end portion 9 of the stabiliser 5, e.g. of the cylindrical
body, at or near a first or lower or drilling end 6 and/or a second
or upper end 7 thereof.
[0126] Typically, each blade 20 comprises at least one edge 21
between the at least one top portion or surface 22 and the at least
one sloped portion or surface 23 thereof.
[0127] Beneficially, the reaming means and/or reinforcing means 10
are provided on at least one blade 20 of the stabiliser 5.
[0128] The stabiliser 5 comprises first reaming means 11 provided
at least at or near a first or lower end portion 6 of the
stabiliser 5, which first end 6 is nearest a drill end thereof, in
use.
[0129] The stabiliser 5 further comprises second reaming means 12
provided at least at or near a second or upper end portion 7 of the
stabiliser 5, which second end 7 is farthest from a drill end
thereof, in use.
[0130] As can be seen from FIGS. 2 and 3, in this embodiment first
and/or second reaming means 11,12 comprise reaming blocks 11a, 12a
protruding or extending at least partially from an end of a top
surface 22 of at least one blade 20 over or onto a sloped surface
23 thereof.
[0131] The first and/or second reaming means 11,12 each have an
outermost surface which is substantially planar. A portion of the
outermost surface of the first and second reaming means 11,12 is
substantially flush or level with the outermost surface 22 of the
blade(s) 20 upon which they are provided. A further portion of the
outermost surface of the first and/or second reaming means 11,12 is
provided radially outward of the respective inclined surface
23.
[0132] In another embodiment, the stabiliser 5 further optionally
comprises third reaming means or reinforcing means 13 provided on
at least one portion, e.g. the sloped portion 23, of at least one
blade 20. By such provision the sloped portion 23 of a blade 20 is,
in use, protected from excessive or premature wear, by e.g.
"undercutting".
[0133] The stabiliser 5 further comprises fourth reaming means 14a
or reinforcing means 14b provided on at least a top portion or
surface 22 of at least one blade 20 thereof.
[0134] Typically, the third 13 and fourth 14a, 14b reaming and/or
reinforcing means are substantially level or flush with an outer
surface 25 at least one blade 20 of the stabiliser 5.
[0135] As shown in FIGS. 1 and 2, the stabiliser further comprises
at least one fifth reaming means and/or reinforcing means 15
provided at least partially along a longitudinal edge 26 of at
least one blade 20.
[0136] In this embodiment, the at least one fifth reaming means
and/or reinforcing means 15 is provided at least partially along a
longitudinal edge 26 facing substantially towards a direction of
rotation of the stabiliser 5, in use. By such provision, reaming
performance is improved and/or the at least one blade 20 is
protected from excessive or premature wear, e.g. by
"undercutting".
[0137] Typically, the first 11, second 12, third 13 and fifth 15
reaming and/or reinforcing means comprise blocks and/or are made
from a diamond-impregnated material, e.g. a diamond-impregnated
tungsten carbide material.
[0138] Typically, the fourth reaming means 14a or reinforcing means
14b are made from an optionally diamond-impregnated tungsten
carbide material.
[0139] The fourth reaming means 14a or reinforcing means 14b
comprise blocks 14c made from a diamond-impregnated tungsten
carbide material and blocks 14d made from a tungsten carbide
material.
[0140] In this embodiment, reaming blocks 14c or reinforcing blocks
14d made from different materials are provided with different
shapes.
[0141] Reaming blocks 14c made from a diamond-impregnated tungsten
carbide material are provided in a circular, hexagonal, or
octagonal shape, and reinforcing blocks 14d made from a
non-reinforced tungsten carbide material are provided in a
rectangular shape.
[0142] In this embodiment, the reaming and/or reinforcing means
11,12,13,14a,15 comprise a combined reaming and reinforcing means,
e.g. provide both a reaming and reinforcing function, whereas the
reinforcing means 14b provide a reinforcing function.
[0143] In this embodiment, the reaming and/or reinforcing means
11,12,13,14a,15 and/or the reinforcing means 14b are provided on
one blade 20 of the stabiliser 5.
[0144] In an alternative embodiment, the reaming and/or reinforcing
means 11,12,13,14a,15 and/or the reinforcing means 14b are provided
on more than one blade 20, e.g. every blade, of the stabiliser
5.
[0145] In this embodiment, the reaming and/or reinforcing means
11,12,13,14a,15 and/or the reinforcing means 14b are provided on
the same blade 20 of the stabiliser 5.
[0146] In another embodiment, each of first, second, third, fourth
and fifth reaming and/or reinforcing means 11,12,13,14a,15 and/or
of reinforcing means 14b are provided independently on one or more
blades of the stabiliser.
[0147] It is understood that the reaming means 10 provided on the
stabiliser 5 of the present invention may fulfil their function
when the stabiliser 5 is in rotational motion, e.g. during normal
drilling mode.
[0148] The reaming and/or reinforcing means 11,12,13,14a,15 and/or
the reinforcing means 14b are made of a material harder than the
material of the body 8 of the stabiliser 5.
[0149] Typically, the stabiliser 5 is made from a low carbon alloy
steel, e.g. a "AISI4145" steel.
[0150] Advantageously, the stabiliser 5 is a downhole drill motor
stabiliser.
[0151] Referring to FIG. 5 there is provided a drill bit according
to a second embodiment of the present invention 40 comprising a
gauge bit 42 at or near a drilling end 45 thereof, and a connection
means 46 for connecting the drill bit 40 to a drill motor assembly.
The connection means 46, e.g. a thread connection, are provided to
connect the drill bit 40 to a motor shaft of the drill motor
assembly.
[0152] In this embodiment, the connection means 46 comprises a
thread connection, e.g. an externally threaded pin 47 configured
for engaging and connecting with a receiving portion, e.g. an
internal thread, of a lower end portion of the shaft. By such
provision, the need for a connector, e.g. a bit box, between the
drill bit 40 and the end of the motor body, e.g. motor shaft, is
eliminated.
[0153] Conveniently, the drill bit further comprises a neck portion
50 provided at or near an upper end of the gauge bit 42 to allow
gripping, e.g. by a bit gripper.
[0154] In this embodiment, the neck portion 50 comprises two
diametrically opposed flat portions 55 to allow gripping, e.g. by a
bit gripper.
[0155] Advantageously, the drill bit 40 is devoid of a bit
sleeve.
[0156] Typically, the drill bit 40 comprises a substantially
cylindrical portion gauge 42 having a length less than or equal to
approximately 1.0 times the nominal bit diameter, and typically in
the range of 1 inch to 1.0 times the nominal bit diameter.
[0157] By such provision the drill bit 40 may be termed a "short
gauge bit" 41.
[0158] The drill bit gauge 42 may have a length in the range of 1''
to 8'', typically 2'' to 6''.
[0159] Typically, the drill bit 42 may be made from a
diamond-impregnated carbide material with a suitable binder
material.
[0160] Referring now to FIG. 6 there is provided a drilling
assembly 30 comprising a stabiliser 5 according to the first
embodiment of the present invention, a drill bit 40 according to
the second embodiment of the present invention, and a drill motor
assembly 60.
[0161] The stabiliser 5 is provided at a lower end of the drill
motor assembly 60, i.e. an end nearest a drill end 45 thereof.
[0162] Typically, the drill motor assembly 60 comprises a tubular
motor body portion 65 adapted for selective rotational movement, a
motor shaft provided within or inside said tubular motor body
portion, and a drill bit attachment means provided at or near a
lower end portion of the motor shaft.
[0163] Typically also, the tubular motor body portion 65 is
attached and/or rotationally connected to the stabiliser 5. By such
provision, rotational motion of the motor body portion 65 causes
rotational motion of the stabiliser 5, e.g. during normal drilling.
Conversely, absence of rotational motion of the motor body portion
65, e.g. during directional or lateral drilling, causes the
stabiliser 5 to remain stationary in relation to the motor
shaft.
[0164] Typically, a lower end portion of the shaft is provided with
an internal thread into which is received an externally threaded
pin 47 of the drill bit 40.
[0165] The assembly is devoid of a connector, e.g. a bit box,
between the drill bit 40 and a lower or drilling end of the motor
body 65, e.g. motor shaft.
[0166] Conveniently, a lower end portion of the stabiliser is
substantially level or flush with a lower end portion of the motor
shaft.
[0167] Preferably, the drill bit 40 is a short gauge drill bit 41.
In the art, a short gauge bit is understood to mean a drill bit
with an outer cylindrical portion the length of which measures less
than or equal to approximately 1.0 times the nominal bit diameter,
and typically in the range of 1 inch to 1.0 times the nominal bit
diameter.
[0168] Conveniently, the drill bit 40,41 comprises a neck portion
50 to allow gripping, e.g. by a bit gripper.
[0169] In one implementation, as shown in FIGS. 1 to 3, the shape
of the stabiliser 5 is substantially concentric in relation to the
motor shaft.
[0170] In this embodiment, the external diameter of the stabiliser
5 diameter is substantially identical to the full gauge diameter of
the drill bit 40,41, i.e. 0 to -1/8'', of the nominal hole
size.
[0171] In another implementation, as shown in FIG. 4, the shape of
the stabiliser 5 is acentric or eccentric in relation to the motor
shaft. The stabiliser 5 displays an offset such that an offset
blade 20a of the stabiliser 5 sweeps a radius equal to or greater
than the bit gauge radius. Typically, the offset radius is 0 to +3
mm of the bit gauge radius.
[0172] Beneficially, the drill bit 40,41 is devoid of a bit sleeve.
By such provision the drill bit relies only on the integral matrix
gauge for stabilisation and the bit overhang is reduced
significantly thereby improving the steerability of the motor
assembly.
[0173] The drill bit gauge 42 has a length in the range of 1'' to
8'', typically 2'' to 6''.
[0174] The distance between a lower or drilling end of the motor
body 65, e.g. motor shaft and/or of the stabiliser and the bit
gauge 42 is in the range of 1'' to 8'', typically 2'' to 6''.
[0175] Typically, the drill bit 40,41 is made from a
diamond-impregnated carbide material with a suitable binder
material.
[0176] Typically the drilling assembly 30 is a downhole drilling
assembly 31.
[0177] Referring to FIGS. 7 to 10 there is provided a drilling
assembly 30' comprising a stabiliser 5' according to a third
embodiment of the present invention. The stabiliser 5' comprises a
lockable means or lock and key mechanism 80.
[0178] The lockable means or lock and key mechanism 80 is adapted
for temporarily and/or releasably locking a drive shaft 70' through
or together with a drill motor stabiliser 5'.
[0179] Advantageously, the drive shaft 70' is a motor drive shaft
71' and/or the stabiliser 5' is a drill motor stabiliser.
[0180] By such provision a lower end portion of the shaft 70'
provided underneath or inside the stabiliser 5' may be held in
position while attaching or detaching a drill bit 40' to/from the
shaft 70'.
[0181] Typically, the lockable means or lock and key mechanism
comprises a lock means 90 and a key means 100.
[0182] The lock means 90 comprises at least one opening, aperture
or slot 91 provided in or through a portion of the stabiliser 5',
and at least one receiving or lock portion 95 provided on at least
one portion of the motor drive shaft 70'.
[0183] Conveniently, in use, the or one of the at least one
openings 91 of the stabiliser 5' is aligned with the or one of the
at least one receiving or lock portions 95 of the motor shaft
70'.
[0184] The at least one opening 91 is openably covered or protected
with covering means 92, e.g. a flap or cover. Such may seek to
prevent, in use, ingress, egress or gathering of debris or drilling
particles in or near the opening 91.
[0185] Typically, the key means 100 comprises at least one handling
portion 101 and at least one engaging portion 102.
[0186] Conveniently, the shape and size of the at least one opening
portion 91 is such that the at least one engaging portion 102 of
the key means 100 may be inserted therethrough.
[0187] Conveniently, the at least one receiving or lock portion 95
of the shaft 70' is adapted for receiving the at least one engaging
portion 102 of the key means 100.
[0188] Typically, the at least one receiving or lock portion 95 of
the shaft 70' comprises e.g. a slot, and the at least one engaging
portion 102 of the key means 100 is e.g. T-shaped.
[0189] Typically, the shaft 70' is provided with one or more, e.g.
two, receiving or lock portions 95, optionally diametrically
opposite one another.
[0190] Typically also, the stabiliser 5' is provided with one or
more, e.g. two, openings 91.
[0191] Preferably, the drill motor stabiliser 5' is a stabiliser
according to the first embodiment of the present invention.
[0192] Preferably, the locking means or lock and key mechanism 80
is adapted for a downhole drill motor assembly 31'.
[0193] Preferably, the downhole drilling assembly 31' comprises a
stabiliser 5', a drill bit 40', and a drill motor assembly 60'.
[0194] Referring now to FIG. 11, there is provided a drilling
assembly 30,30' comprising a stabiliser 5,5' according to a first
or third embodiment of the present invention, a drill motor
assembly 60,60', and a drill bit according to a second embodiment
of the present invention (not shown).
[0195] In one implementation, the drilling motor assembly 60,60'
comprises a deviating device 110,110', e.g. an offset stabiliser or
a bend.
[0196] When the shape of the stabiliser 5,5' of the present
invention is acentric or eccentric in relation to the motor shaft
70,70' and/or motor body portion 65,65', the acentric or eccentric
stabiliser 5,5' may be aligned with and/or relative to the
deviating device 110,110'. By such provision, deviation of the
drilling assembly 30,30' by the deviating device 110,110' may be
adjusted, improved and/or increased by aligning the acentric or
eccentric stabiliser 5,5' with and/or relative to the deviating
device 110,110'. Typically, deviation will occur in a direction
opposite the offset blades 20a of the stabiliser 5,5'.
[0197] It will be appreciated that the embodiments of the present
invention hereinbefore described are given by way of example only
and are not meant to limit the scope thereof in any way.
* * * * *